Chromosome-level Genome Assembly of the Chinese Longsnout Catfish Leiocassis Longirostris.

The Chinese longsnout catfish ( Leiocassis longirostris Günther) is one of the most economically important freshwater fish in China. As wild populations have declined sharply in recent years, it is also a valuable model for research on sexual dimorphism, comparative biology, and conservation. However, the current lack of high-quality chromosome-level genome information for the species hinders the advancement of comparative genomic analysis and evolutionary studies. Therefore, we constructed the first high-quality chromosome-level reference genome for L. longirostris. The total genome was 703.19 Mb, with 389 contigs and contig N50 length of 4.29 Mb. Using high-throughput chromosome conformation capture (Hi-C) data, the genome sequences (685.53 Mb) were scaffolded into 26 chromosomes ranging from 17.36 to 43.97 Mb, resulting in a chromosomal anchoring rate for the genome of 97.44%. In total, 23 708 protein-coding genes were identified in the genome. Phylogenetic analysis indicated that L. longirostris and its closest related species P. fulvidraco diverged approximately 26.6 million years ago. This high-quality reference genome of L. longirostris should pave the way for future genomic comparisons and evolutionary research.